I have a different service running on FTL default port and so FTL service was not properly started. I searched quite a long time to discover why the Dashboard never loaded and finally found the reason.

This patch counts empty lines and dies properly with a JSON error. This fixed my issue.

Also I have pi-hole running with apache2 and so no /var/log/lighttpd/error.log exists.
Fix: Try apache2 logging location and if not found then write log to a /tmp file.

Signed-off-by: Philipp Kolmann <philipp@kolmann.at>

scripts/pi-hole/php/FTL.php

@@ -26,7 +26,7 @@ function sendRequestFTL($requestin)
 	global $socket;
 
 	$request = ">".$requestin;
-	fwrite($socket, $request) or die("Could not send data to server\n");
+	fwrite($socket, $request) or die('{"error":"Could not send data to server"}');
 }
 
 function getResponseFTL()
@@ -35,9 +35,16 @@ function getResponseFTL()
 
 	$response = [];
 
+	$errCount = 0;
 	while(true)
 	{
 		$out = fgets($socket);
+		file_put_contents('/tmp/pihole.txt', $out, FILE_APPEND);
+		if ($out == "") $errCount++;
+		if ($errCount > 100) {
+			// Tried 100 times, but never got proper reply, fail to prevent busy loop
+			die('{"error":"Tried 100 times to connect to FTL server, but never got proper reply. Please check Port and logs!"}');
+		}
 		if(strrpos($out,"---EOM---") !== false)
 			break;
 

scripts/pi-hole/php/auth.php

@@ -10,6 +10,14 @@ require_once('func.php');
 $ERRORLOG = getenv('PHP_ERROR_LOG');
 if (empty($ERRORLOG)) {
     $ERRORLOG = '/var/log/lighttpd/error.log';
+
+    if (!file_exists($ERRORLOG) || !is_writable($ERRORLOG)) {
+	    $ERRORLOG = '/var/log/apache2/error.log';
+
+	    if (!file_exists($ERRORLOG) || !is_writable($ERRORLOG)) {
+		    $ERRORLOG = '/tmp/pi-hole-error.log';
+	    }
+    }
 }
 
 function pi_log($message) {